For protecting human health and preserving the clean environment, current regulations stipulate acceptable levels of particulate emissions based on the mass collected on filters obtained by sampling in diluted exhaust. Such regulations will be imposed not only on-road engines but also off-road engines. From the point of view of human health [1], so-called nano-particle (d<50nm) is thought to be nuisance because it could reach deeper lung tissue. So, many researches have been done in this research field [2].

Dramatic changes in PM emission are evident in the data from both EEPS and filters according to the variation in engine operating modes, such as speeds and loads. This illustrates that the physical characteristics of PM is highly dependent on the engine operating conditions. The results also show that the considerable variation of PM emitted during NRTC test cycle. These results indicate the physical characteristics of PM are tremendously varied with practical use.